Frontend overhaul: NetBox-style detail pages, selectable columns, data sources

- Cultivar/species detail pages rewritten with two-column card layout, attribute tables, em-dash placeholders
- Column toggle + per-page selector on all list pages (families, species, cultivars, suppliers)
- Species list: table/card view toggle with family, layer, N-fixer, uses columns
- Cultivar detail: supplier links with SKU/price/product URL, species info section
- Data sources page (/sources) with attribution for all 10 data sources
- Fixed Cultivar/Species structs with #[serde(default)] for API compatibility
- Added table_controls component (reusable column toggle + per-page selector)
- Removed max-width constraint on content area for full-width tables
- Fixed route conflicts: merged {slug}/{id} into single {ref} routes
- Removed PostgreSQL enum types (plant_layer, drought_tolerance, etc.) in favor of TEXT
- Fixed API per_page parameter support across all list endpoints

herbapi-ui/src/app.rs

@@ -27,6 +27,8 @@ pub enum Route {
         SupplierDetail { slug: String },
         #[route("/search")]
         SearchPage {},
+        #[route("/sources")]
+        Sources {},
     #[end_layout]
     #[route("/:..segments")]
     NotFound { segments: Vec<String> },
@@ -62,6 +64,7 @@ fn Layout() -> Element {
                     NavLink { to: Route::CultivarList {}, label: "Cultivars" }
                     NavLink { to: Route::SupplierList {}, label: "Suppliers" }
                     NavLink { to: Route::SearchPage {}, label: "Search" }
+                    NavLink { to: Route::Sources {}, label: "Sources" }
                 }
                 div { class: "sidebar-user",
                     if let Some(ref u) = user {
@@ -104,5 +107,6 @@ pub use crate::pages::cultivars::{CultivarDetail, CultivarList};
 pub use crate::pages::families::{FamilyDetail, FamilyList};
 pub use crate::pages::home::Home;
 pub use crate::pages::search::SearchPage;
+pub use crate::pages::sources::Sources;
 pub use crate::pages::species::{SpeciesDetail, SpeciesList};
 pub use crate::pages::suppliers::{SupplierDetail, SupplierList};